The objective of the proposed study is to secure evidence of synchronized cell assembly activity in the brain. In particular, to seek and characterize synchronized firing patterns among two or more simultaneously recorded single units in striate cortex during active scanning of specified targets. It is hypothesized that much of the information transmitted within the nervous system is in the form of temporal correlations among the outputs of neurons and cannot be revealed by recording from single units one at a time. It is further hypothesized that in animals processing visual information cortical neurons execute synchronized cooperative activity only detectable in an experimental paradigm that permits unrestrained visual exploration of targets. Chronically implanted microelectrodes will be used to record from one or more single units in striate cortex during the active scanning of experimentally defined targets. Utilizing the high recording stability of implanted fine wire microelectrodes, the receptive fields of the neurons will be mapped in a session prior to the experimental run. During the experiment proper, spike trains will be electronically catalogued with respect to (1) the instantaneous spatial relations between the receptive fields and the viewing targets mounted on a screen before the animal, and (2) the instantaneous state of eye movement. Mathematical methods, developed for the treatment of large neuron networks, will be employed as an aid in evaluating the implications of the physiological results.